1. Field of the Invention:
This invention relates to a multiple glazed unit and more particularly to a multiple glazed unit having inner glass sheet(s) mounted within a spacer.
2. Discussion of the Prior Art and Technical Problems:
Multiple glazed units having three or more transparent sheets are known in the prior art and taught in U.S. Pat. Nos. 2,235,680; 2,525,717; 2,741,809; 2,838,809; 2,883,718; 2,934,801; 2,966,435; 3,544,294; 3,837,129 and 3,872,198 to name a few.
In general, U.S. Pat. Nos. 2,741,809; 2,838,809; 2,934,801; 2,966,434 and 3,544,294 each teach a multiple glazed unit having a plurality of glass sheets separated by a spacer positioned between adjacent glass sheets. Although the multiple glazed units taught in the above-mentioned patents are acceptable, they are expensive to construct. More particularly, positioning a spacer between adjacent glass sheets requires two spacers for a triple glazed unit thereby increasing material costs. Further, increased time is required to construct two spacers and mount them between adjacent glass sheets than to construct one spacer. This cost in material and time increases as the number of glass sheets employed increases.
U.S. Pat. Nos. 2,525,717; 2,883,718; and 3,872,198 each teach a multiple glazed unit having three glass sheets separated by a spacer. In general, the spacer has a base having a plurality of grooves for receiving edge of a glass sheet. In order to form a good hermetic seal, close tolerances between walls of the groove and adjacent surfaces of the glass sheet mounted therein must be maintained to avoid formation of voids in the seal. If voids are present, air will move between the glass sheets reducing the insulating quality of the unit.
U.S. Pat. No. 2,235,680 teaches a multiple glazed unit having in one embodiment three glass sheets held in spaced relation by a metal strip adhered to peripheral edge portions of each glass sheet and marginal edge portions of the outer sheets. The drawback of the glazed unit taught in U.S. Pat. No. 2,235,680 is that it does not have provisions for providing a desiccating material to absorb moisture in the airspace between the glass sheets. Therefore, care has to be exercised during fabrication of the unit to assure that the air in the airspace is free of moisture. If moisture is present, it condenses on the window and obstructs the view of the observer.
U.S. Pat. No. 3,837,129 teaches a multiple glazed unit having two glass sheets and a plastic middle sheet. The middle sheet is mounted in a U-shaped member which engages the middle sheet by the extremities of the U-limbs and clamps the middle sheet by its inherent resistance. Spacers and the U-shaped member separate the outer glass sheets from the middle sheet. Although the unit taught in U.S. Pat. No. 2,837,129 is suitable for its intended purpose, there are limitations. More particularly, the unit is expensive to construct and requires three discrete spacers, namely, two metal spacers and the U-shaped member.
It would be advantageous, therefore, to provide a multiple glazed unit, e.g., a triple glazed unit that does not have the limitations and drawbacks of the multiple glazed units taught in the prior art.